Yarn and fabric production



Patented Oct. 8, 1940 UNITED STATES PATENT orr cE 2,216,799 YARN AND FABRIC PRODUCTION John L. Baggett, Cumberland, Md, assignor to Celanese Corporation of America, a corporation of Delaware No Drawing Application March 11, 1938, Serial No. 195,309 a 6 Claims; (Cl, 260-615) lose, where the yarns are treated. with a dress ing containing a formal-ether having the formula i where R is hydrogen or an alkyl or phenolresidue and the two free oxygen bonds are linked to two monovalent radicles derived from polyhydric alcohols or from hydroxy-carboxylic acids, or are linked, to a bivalent radicle derived from a polyhydric alcohol or a hydro-carboxylic acid, Other objects of the invention will appear from the following detailed description.

In the production of fabrics, especially knitted fabrics, from artificial filaments, there is often applied to the yarns a dressing containing a formal-ether. Thisdressing is applied to the yarns to make them more amenable to textile opera-' tions. The amount of dressing applied to the yarns and the percentage of formal-ether in the dressing varies according to the particular textile operation to which the yarns will be subjected. For instancathe amount of formal-ether applied to the yarn may vary from less than 1% to more than based on the weight of the yarn. l

In textile operations employing organic derivative of cellulose yarns the waste yarn containing large amounts of the formal-ether dressing could not heretofore conveniently be reworked by redissolving and respinning into yarns Without first removing the dressing. The removal of the formal-ether dressing was very difficult and attempts to remove it had deleterious eifects on the organic derivative of cellulose and also destroyed the formal-ether. By employing this invention, however, the organic derivative of cellulose'yarn may be recovered in a condition suitable for respinning and also the formal- 5 ether isobtained in a condition suitable for re- This invention resulphonated fatty alcohols, etc.

use as a dressing for further batches of yarn.

Since approximately of the formal-ether cost is raw material cost, the recovery thereof effects a substantial economy even without considering the value of the recovered organic derivative of cellulose.

In accordance with my invention, I separate organic derivative of cellulose yarns or material from the formal-ether dressing, that had been applied thereto, in such a manner that both the organic derivative of cellulose material and the formal-ether of the dressing are capable of being reused and have the same qualities as freshly prepared material. This separation is effected by extracting the dressing from the organic derivative of cellulose with toluene, then separating the mixed toluene from the dressing by a simple distillation which removes most of the toluene, and finally removing the remaining toluene by adding water to the still, which water it and toluene leave the still as a constant boiling mixture at 84 C.

This invention is applicable to the recotery of cellulose acetate or other organic derivatives of cellulosesuch as organic cellulose esters and cellulose ethers.

Examples of cellulose esters are cellulose formate, cellulose propionate and cellulose butyrate, while examples of cellulose ethers are ethyl cellulose, methyl cellulose and benzyl cellulose. Although the invention is principally concerned with the recovery of the formal-ethers, and organic derivative of cellulose material in the form of yarns and fabrics, the organic derivative of cellulose. material may be recovered from processes involving the manufacture of organic derivative of cellulose films, straws, bristies and the like, Where formal-ethers had been employed.

This invention is applicable to the separation of organic derivatives of cellulose from dressings 1 containing a formal-ether alone or mixed with lubricants, such as mineral oil, vegetable oil, sulphonated vegetable oils, oxidized vegetable oils,

The formal- ,ether, as stated above, is a compound having the formula H o J- 0 t where R is hydrogen or an alkyl or phenyl resi-- due and the two free oxygen bonds are linked to two monovalent radicles derived from polyhydric alcohols or from hydroxy-carboxylic acids,

or are linked to a bivalent radicle derived from a polyhydric alcohol or a hydroxy-carboxylic acid, and obtainable by the condensation of an aldehyde such as formaldehyde, acetaldehyde, butyraldehyde or benzaldehyde with an aliphatic 'hydroxy compound such as, for example, a polyhydric alcohol, a partial ether of a polyhydric alcohol, or an aliphatic hydroxy carboxylic acid. This type of ether is referred to in the specification and in the claims as a formal-ether.

Formal-ethers of the present invention may be made by the condensation of formaldehyde, formalin, tri-hydroxy-methylene, butyraldehyde or paraformaldehyde, in the presence or absence of an acid catalyst, with simple polyhydric alcohols such as glycerol, ethylene glycol or propylene glycol, or substituted polyhydric alcohols such as glycerol mono-chlorohydrin or diethylene glycol. Examples of partial ethers of polyhydric alcohols that may be employed for making the formal-ether of the type above defined are the mono-methyl ether of ethylene glycol, the monoethyl ether of ethylene glycol, and the monomethyl or ethyl ether of propylene glycol or of diethylene glycol. Examples of hydroxy carboxylic acids that may be used for preparing the formal-ethers of the type above defined are alpha-hydroxy-iso-butyric acid, alpha-hydroxy normal butyric acid, glycollic acid, lactic acid, etc. Examples of acid catalysts that may be employed for promoting the condensation are ferric chloride or other acid salts hydrochloric acid, sulphuric acid, phosphoric acid or other strong or weak mineral acids.

Generally, the formal-ethers employed in dressings for yarns are of non-volatile type having a boiling point above, say, 140 C. and are soluble in or at least miscible with water.

An example of a dressing employed to a large extent on yarns of cellulose acetate is one composed of '75 to 85 parts of the formal-ether formed by the condensation of formaldehyde with a mono-methyl ether of ethylene glycol, 12 to 20 parts of oxidized olive oil and 3 to 8 parts of olive oil. Yarns produced for the knitting trade may contain as high as or more, based on the weight of the yarn, of this finish.

The process of this invention comprises, essentially, extracting the formal-ether dressing from the yarn mass with successive washes of cold toluene, the subsequent removal of the residual toluene from the yarn by steaming and the recovery of the formal-ether dressing from the solvent by distillation. For better clarity the following example is given of a single charge of waste cellulose acetate yarn.

Example An extractor is loosely filled with from 250 to 2'75 pounds of cellulose acetate yarn. This yarn rests on a perforated disc on the bottom of the extractor. This disc is in turn attached to a rod which runs through the yarn to the top of the extractor. After charging, the top is tightly bolted on and four washes each containing about '75 gallons of toluene are put through. It is found necessary to fill the extractor completely and drain out each time. The pumping of the toluene through the yarn continuously is not satisfactory in that the toluene tends to channel a course through the yarn mass. The residual formalether dressing left on the yarn after the washes will average less than 1%. If more residual dressing remains a 5th or 6th wash may be given the yarn. The yarn retains, however, about 1 to 2 times its own weight of toluene. This toluene is removed with live steam. For instance, about 12 jets running about 2 or 3 inches into the bottom of the yarn mass serve to introduce the steam. The steam and toluene are condensed and then separated, the water going into the waste receptacle or sewer and the toluene going back in to the process. The mixture of toluene and formal-ether dressing is introduced into a still wherein most of the toluene is taken off by simple distillation. The final small amount of toluene remaining in the mixture is removed by the addition of a very small amount of water. The water and toluene leave together as a constant boiling mixture at 84 C. The time required to run through a batch of yarn is approximately 4 hours, that is, an hour and a half for the extraction, a half hour to charge and recharge, and two hours for steaming.

The cellulose acetate of the yarn recovered is found to be in substantially the condition as when it was first formed and may be redissolved and respun into yarn or reworked in any manner that freshly made cellulose acetate is worked.

The dressing remaining in the still after re- The above description has been limited somewhat to yarns. However, this invention is applicable to the recovery of dressing from fabrics. For instance, fabrics which are knitted from yarns containing a high percentage of the formalether dressing may be given 2 to 3 washes with toluene reducing the amount of dressing on the yarn to about 3%. The fabric then may be dyed and finished in the usual manner. Thus, the amount of dressing above 2 to 3% is recovered in a condition capable of being reused and the control of the dye baths is simplified. The invention also is intended to cover the recovery of organic derivatives of cellulose and the dressing from waste fabrics such as ends, swatches, etc. cut from the piece during their manufacture.

While in the above example a centrifugal extractor was employed, it is to be understood that any type of washing may be employed accompanied by a draining of the mixed toluene and dressing from the waste material and recharging with fresh toluene. It is preferable to maintain the toluene at below C. and even more preferable to employ cold toluene of between 15 and 20 C.

It is to be understood that the foregoing detailed description is merely given by way of example and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. In a process for recovering formal-ethers from organic derivative of cellulose textile materials having a formal-ether dressing applied thereto, the steps of collecting the material, extracting the dressing from the material with toluene and separating the formal-ether from the toluene by distillation.

2. In a process for recovering formal-ethers from cellulose acetate textile materials having a Iorma1-ether dressing applied thereto, the steps of collecting the material, extracting the dressing from the material with toluene and separating the formal-ether from the toluene by distillation.

3., In a process for recovering formal-ethers from cellulose acetate textile materials having *a formal-ether dressing applied thereto, the steps of collecting the material, extracting the dressing from the material with successive washes of toluene and separating the formal-ether from the toluene by distillation.

4. In a process for recovering formal-ethers from cellulose acetate textile materials having a formal-ether dressing applied thereto, the steps of collecting the material, extracting the dressing from the material with successive Washes of cold toluene and separating the formal-ether from the toluene by distillation.

5. In a process for recovering formal-ethers from cellulose acetate textile materials having a formal-ether dressing applied thereto, the steps of collecting the material, extracting the dresshaving a formal-ether dressing applied thereto, the steps of collecting the Waste material, extracting the dressing from the Waste material with successive Washes of toluene, separating the major portion of the toluene from the formal-ether by distillation, addingwater to the residual toluene formal-ether solution in an amount just sufficient to form an azeotropic mixture with the residual toluene and distilling off the water and residual toluene together as the azeotropic mixture whereby the formal-ether is freed of substantially all of the toluene.

JOHN L. BAGGETT. 

